


8fcL 



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Class S5S3 

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SMITHSONIAN DKl'OSIT. 



[from the AMERICAN JOURNAL OF SCIENCE, VOL. XXXII, SEPT. 1861.] 



AGRICULTURAL CHEMISTRY-SOIL-ANALYSIS. 

NOTICE OF THE AGRICULTURAL CHEMISTRY OF THE GEO- 
LOGICAL SURVEYS OF KENTUCKY- AND ARKANSAS* 

~^^H> j7 BY PROF. S. W. JOHNSON. 

>^^^j^ OF YALE COLLEO'te. 

^5, . 

In no country has there been so much popular appreciation of 
practical science as in the United States of America. Scarcely 
one of the States is without its volume or volumes of Geological 
and Natural History Reports, and though some of them have 
been content to conhne the work to the merest outline of the 
general and industrial geology of their territory, and have ex- 
pended but a few hundi^eds of dollars in the undertaking, others, 
like New York, have embraced all the branches of Natural Sci- 
ence in their survey, have prolonged the work of exploration or 
elaboration through many years, and have devoted money to 
these objects with unsparing hand. 

The results of these surveys as they stand recorded in the 
numerous volumes published by the States and by the General 
Government, are of very unequal merit, as might be expected 
from the wide range of country explored, from the various degrees 
of interest and appreciation governing the many Legislatures 
which have authorized these, labors and from the exceedingly 
unequal ability of the^dividuals charged with their execution. 

These explorations have originated in all cases with our scien- 
tific men. It is their influence either brought to^oear immediately 
upon the legislative bodies, or exerted less directly through 
cultivated and public spirited persons to whom the possible 
benefits of geological surveys have been explained — that has 
accomplished this vast work. 

The enterprises of which we speak being sustained pecuniarily 
at the expense of the people, and depending from year to year 
in many cases upon the popular vote, it has been not only politic 
but right to exhibit at the outset the prospects of pecuniary 
return for the required outlay of means, as an inducement to 
support such undertakings. It has been no less proper in pre- 
senting the results of the surveys, to lay stress on the discoveries 
having industrial bearings which are the fruits of the work. 

In those States where large quantities of metallic ores occur, 
the interest of capitalists engaged in mining has often sufiiced to 

* 1st, 2d. Sd and 4th Reports of the Geological Survey of Kentucky ] 854-60: 
2d Report of the Geological Reconnoisance of Arkansas, 1860: Agricultural Chem- 
istry and Geology by Dr. D. D. Owen, principal Geologist, and Dr. Robert Pbteb, 
Chemical Assistant. 
Am. Joub. Sci.— Second Sbbies, Vol. XXXII, No. 95.— Sept., 1861. 
30 



2 >S. W. Johnson on the Soil-analyses of the [234] 

inaugurate a geological survey. In other states the agricultural 
sentiment has had to be operated upon. 

Great results have been promised to agriculture from the appli- 
cations of geology and chemistry, and a great deal of labor has 
been performed in the attempt to satisfy the hopes that have 
been thus excited. 

The chief object of the present notice is to inquire what has 
been really accomplished for the good of the farmer, by the sci- 
entific surveys that have been hitherto prosecuted in this country. 

The labors of Dr. Peter in connection with the Kentucky and 
Arkansas Surveys being the most recent and extended attempts 
of this kind, we shall make them the basis of our inquiries. 

If we except a few pages of general remarks on the theory of 
vegetable nutrition, &c., which while useful to the practical readers 
of the Keport contain no new facts or principles, — the whole 
effort of Dr. Peter has been concentrated on the analysis of soils, 
marls, rocks and ashes. He publishes in the four Kentucky Re- 
ports analyses of 375 soils, and in the Arkansas Report, 187, in all 
662 soil analyses. Besitles, we find the results of examinations 
of 145 rocks, shales, &c., and of 38 ashes of plants, making a 
grand total of 795 agricultural analyses. 

The agricultural fruits of the surveys of Kentucky and Ar- 
kansas are then to be sought in these analyses. 

It certainly will strike all that the amount of work performed 
by Dr. Peter is unusually great. It is now but six years since 
the Kentucky survey was commenced and in that time the Dr. 
has not only analyzed 795 soils, but has executed 516 analyses of 
ores, slags, mineral waters and coals, making an average of two 
analyses for every three days of this whole period. This labor 
Dr. Peter states he has accomplished with the help of one intelli- 
gent assistant, and by a special organization of his laboratory 
and his operations whereby the utmost economy of time was 
secured. We have had such experience of the advantages of a 
similar system, that we are not prepared to doubt that the chemist 
who adopts a plan of analysis which fully satisfies him, and from 
which he never departs, may execute such an amount of work. 
At the same time we must bear in mind that the only control 
Dr. Peter offers for the accuracy of his results is, that the sum of 
the weights of the separated ingredients equals their original 
conjoined weight, no time being allowed to repeat a determina- 
tion, or to prove the purity of a precipitate. 

The Analytical Process followed in these analyses is not by 
any means so minute and full as we should be warranted to 
expect, when their author declares (4th Ky. Rep., p. 57) that 
"such a work to be eminently useful must be thorough and 
exhaustive ;" for soluble silica, chlorine, nitric acid and ammonia 
are not at all estimated, and the condition of the iron, whether 
protoxyd or peroxyd, is not noticed. It is worthy of notice that 



b 



[235] Geological Surveys of Kentucky and Arkansas. 3 

carbonic acid and lime are always present in atomic proportions 
in the soils latterly analyzed, no excess of either ingredient being 
mentioned in the results. Carbonic acid however is not noticed 
in the description of the analytical process, and that figuring in 
the analyses does not appear to have been directly estimated, 
but to have come from the oxalic acid of the reagent shelf. 

If, as might easily happen, the contrary not being proved, a 
portion of the lime dissolved by hydrochloric acid exists in these 
soils as silicate, sulphate or phosphate, then the assumption that 
it is united to carbonic acid introduces an error into the summing 
up (which in many cases is exactly 100) and shows that a quan- 
tity of some other ingredient has been overlooked. 

For the estimation of phosphoric acid a highly modified form 
of Sonnenschein's process is employed, but our author does not 
give the figures which prove that his changes are improvements. 

Admitting however that the analyses are correct — we next 
inquire what is their value — what useful deductions from them 
appear in these Reports. 

In the introduction to Vol. i, Kentucky Survey, page 13, Dr. 
Owen says: " By consulting the numerous interesting results 
obtained by the chemical analyses of the soils embodied in the 
pages of this report, abundant evidence will be gathered of the 
vital necessity of wide dissemination amongst the farming com- 
munity, of the knowledge to be obtained by a correct insight 
into their chemical constitution." In the same volume, page 
373, Dr. Peter remarks that he was impressed " that when the 
composition of our Kentucky soils and minerals in general, is 
once accurately established, their applications to our wants and 
uses would be obvious to all well informed persons. He has 
therefore consumed the time mainly in the analyses, and made 
up his report principally of the results." 

In the agricultural section of the Arkansas Survey, p. 47, Dr. 
Owen says: — "principally from chemical soil-analyses can the 
agriculturist form an intelligent opinion as to the comparative 
fertility of soils, and their suitability to the growth of certain 
plants, as well as judge what applications may be required in the 
way of lime, bone earth, plaster of Paris, ashes, or salts of pot- 
ash, soda, &c." 

Dr. Peter, in the same volume, page 166-7, observes: — "It is 
believed that by no other mode than by chemical analysis or by 
the more tedious and laborious method of actual experience, in 
cropping for a series of years and publishing a record of the 
same, can the actual nature, capabilities and value of the various 
soils of a State be presented to the public ; and that by institu- 
ting this Geologico- Agricultural Surve}', the State of Arkansas 
not only aids materially in the progress of the general science 
of the civilized world, and that of the soil in particular, but 
takes the most effectual mode of making known to the enlight- 
ened immigrant her agricultural riches. In this she has followed 



4 S. W. Johnson on the Soil-analyses of the [236] 

the wise lead of the older state of Kentucky, in which, since 
the institution of her geological surve}', the value of the land 
in the regions examined and reported on has been very greatly 
enhanced." 

In the Agricultural Geology of Kentucky, Report 2d, p. 9, 
Dr. Owen says: " Placing implicit reliance on the capabilities of 
chemical science to indicate by the analyses of soils, the ingre- 
dients removed by the cultivation and harvesting of successive 
crops, it was hoped that by collecting samples of the virgin soil, 
and of the same soil from an adjacent old field, that not only 
the different substances assimilated out of the soil could be as- 
certained, but also the exact proportion of these so that the far- 
mer might know precisely what must be restored to the land to 
bring back its original fertility." 

These quotations sufficiently show what were the opinions 
which led our author to devote such an amount of labor to the 
analysis of soils, and indicate in general, what results were ex- 
pected. 

In the 2d Arkansas Report, p. 49 et seq., Dr. Owen " proceeds 
to explain in what way soil-analysis becomes of value to the 
farmer." He desires ^' to call particular attention to this subject, 
because the opinion has been expressed even in this year (1860), 
and by those having a high standing in the scientific world, that 
chemistry is incapable of conveying any useful information to 
the farmer by analyzing his soil." 

On the six following pages of the 2d Ark. Rep., and on page 
80 of the 4th Ky. Rep., Dr. Owen gives the most complete resume 
of the teachings of soil-analysis which we are able to find in 
the fi.ve volumes before us, and as these are his latest writings 
on the subject, and as he then had the data of 389 analyses, viz. 
of 187 Arkansas soils and 202 in the three volumes of the Ken- 
tucky Report, — these being refrered to on the pages we are quoting 
from, — we are warranted in considering what he has here pre- 
sented, as embodying the strong points in favor of soil analysis. 
We will notice them separately as gathered from both Reports. 

1st. " Any one who will take the trouble to inspect the analy- 
ses of the 187 Arkansas soils will see that the relative propor- 
tions of the eleven mineral constituents of these soils is very 
accurately given." — 2d Ark. Rej)., p. 49. 

If we admit fully that Dr. Peter's analyses represent with 
fair accuracy the composition of the two grammes of soil he ex- 
perimented with in each instance, we do not therefore allow 
that the composition of "these soils" considered as representing 
geological formations, or large agricultural districts, or even 
single fields, is "very accurately' given." 

Here at the outset the distinguished gentlemen who have con- 
ducted the 'geologico-' and 'chemico-agriculturai' part of the 
Kentucky and Arkansas surveys have taken for granted, what 



[237] Geological Surveys of Kentucky and Arkansas. 5 

being an error, overturns their whole reasoning, and renders 
their soil-analyses comparatively worthless. 

Years ago, following the teachers of agricultural chemistry in 
this country and England, we believed that soil-analyses were 
adapted to be of exceeding use to farmers. Having practised 
analytical chemistry sufficiently to undertake the work, we pro- 
ceeded, when on a vacation visit, to collect some farm soils for 
the purpose of applying our skill and knowledge. On putting 
down the spade and post-augur into the drift overlying the low- 
est Silurian of Northern New York, we were at once struck 
with the difficulty of procuring an average specimen. The soil 
for a depth varying from two to six inches was quite fine, but 
below that depth largely mixed with gravel. On comparing 
different samples taken from a small area, it was plain that the 
«oil was not a fit subject for analysis. The relative quantities 
of organic matter as indicated by the color of the surface of small 
stones, — some quartz and granitic, others slate and limestone 
of several geological members, — were astonishingly variable. 
Here we found the soil sandy, there it was clay. To take a 
sample from one place was to do obvious injustice to the sixty- 
acre field. To take it from a dozen places would not render the 
selection of a fair sample any more certain. Then as to depth 
— was it proper to go down six inches, one foot, or how far? 
Had the field been a bed of iron ore, assays of a dozen samples 
taken from different parts would have indicated very satisfacto- 
rily the general value of the deposit, would have served as data 
for buying and selling the property, because the worth of an 
unworked bed of such ore depends less upon its content of iron 
than upon external circumstances which affect the extracting of 
the metal. Had the field been covered with rich dressed copper 
ore to the depth of six inches, it would have been necessary to 
divide it up into small parcels of a few tons, average these care- 
fully and as carefully assay each one. No one would risk pur- 
chasing a hundred thousand tons of copper ore on the analysis 
of one or of a dozen samples, because it is impracticable to in- 
termix or average such a mass of material as that a dozen sam- 
ples shall accurately represent it. 

We hold it therefore as the first objection to soil-analyses that 
to procure a specimen which accurately and certainly represent a 
field or district, is practically impossible in the majority of cases, 
and if possible^ requires a series of analyses to prove the fact. 

This argument applies with the greater force when we con- 
sider how small a proportion of the ingredients of a soil are of 
any immediate use in feeding crops. The really active nutrient 
matters of a soil are not reckoned by per cents nor by tenths of 
per cents, but by the minutest fractions, 

A heavy crop of thirtj^-seven bushels of wheat, grain and 
straw included, removes from an acre of land but 300 lbs. total 



6 'S'. W. Johnson on the Soit-analyses of the [238] 

of mineral matters. According to Dr. Peter's weighings on some 
of the Kentucky soils, we may assume, that taken to the depth 
of a foot, an acre of soil weighs 3,000,000 lbs. All that is re- 
moved by the heaviest wheat crop then in one year is but ^-^ lo-o, 
or 0-0038+ per cent. 

It follows that the annual removal of the heaviest crop of 
wheat from a soil for 100 years diminishes its mineral matters 
by less than 04 per cent. If then, in the selection of a sample, 
the aveVage composition is departed from to the amount of 4 
parts in 1000, the analysis may misrepresent the soil, by the 
value of 3700 bushels of wheat per acre, or by what represents, 
so far as mineral ingredients can, the fertility of a century. 

What freaks and accidents is not the soil-analyst the sport of? 
A bird, squirrel, or dog relieving nature at the spot where he 
collects his sample, innocently magnifies the phosphoric acid or 
alkalies of the surrounding thousand acres a hundred fold. 
The soil gathered toward the end of a long rain, whereby its 
soluble matters are carried deep into the subsoil, is declared poor, 
by analysis, whereas if taken after a fortnight of drought it 
might appear extraordinarily fertile. Boussingauit found in his 
rich garden soil in June, during wet weather, 00003-1 per cent 
of nitric acid. In the following September, after a period of 
dryness, it contained 0*0093 per cent, or twenty-seven times as 
much as in June. This ingredient is indeed more liable to fluc- 
tuation in amount than any other, both because it is formed in 
the soil, and because it is not subject to the absorbent action 
which the soil exercises over most other of its soluble constitu- 
ents ; but the same variation occurs among the other ingredients 
according to the direction of the capillary movement of the soil- 
water, though in less degree. 

Independently however of all considerations and calculations 
like the above, we have proof — evidence at least that supports 
these considerations, and has never been publicly refuted — that 
it is practically impossible to obtain average specimens of the 
soil. I refer to investigations made as long ago as 1846-9 under 
the direction of the Prussian " Landes Oekonomie Collegium,^'' 
and reported by the distinguished Magnus. The account of 
these experiments is given in detail in Erdmann's Journal fiir 
Praktische Chemie, vol. xlviii, pp. 447 et seq. 

The ^''Landes Oekonomie CoUegiian" at that time carried on 
systematic experiments in agriculture at fourteen distinct stations 
scattered through the Prussian domain. The trials which we 
now speak of, were made for the ostensible purpose of studying 
the exhaustion of the soil by cropping. The plan was to analyze 
the fourteen soils, the history of which for years previous was 
accurately known, then crop them with rape until "exhausted," 
then compare together the original composition of the soils with 
their composition after exhaustion, taking into account as well, 



[239] Geological Surveys of KentucJcy and Arkansas. 7 

the composition of the crops removed. The research began 
with collecting and analyzing the soils. In order to meet as far 
as possible the difficulties of securing average specimens, equal 
portions of the soil of each field were taken with the spade at 
ten or twelve different points, and thoroughly intermixed ; each 
sample was then passed through a sieve, the holes of which were 
two square lines in area, so as to remove all coarser stones, then 
again well worked over to complete the mixture. Of each sam- 
ple three separate portions were analyzed, in most cases by dif- 
ferent operators. The analyses were made by, or under the 
guidance of, the ablest chemists of Germany. They were made 
according to a prescribed scheme, and that there should be no 
reason to slight the work, the work was paid for. It is true that 
analytical chemistry was not so advanced in 1846 as now. It is 
true that the methods then practised for estimating phosphoric 
acid and some other substances were not as perfect as they now 
are ; but for the most part the analyses then made are as accu- 
rate as any that could be executed to-day. It cannot be sup- 
posed for a moment that analysts like Eammelsberg, Bodecker, 
Genth, Debus, Knop, Heintz, Krocker, Marchand, VV^eidenbusch, 
Sonnenschein, Varrentrap, Weber, &c. &c., would by fault of 
method or by carelessness return anything but results that were 
accurate, as far as it was possible to make them such. We cannot 
suppose that their determinations of lime, oxyd of iron, potash 
and sulphuric acid, substances estimated then by the same meth- 
ods that are now employed, would vary if they were supplied with 
homogeneous material to operate upon. But let us look at some 
of their figures. We tabulate a number of them taken at ran- 



dom: 












Soil of 

Eldena, 


!? 


Lime. 

0-39 
0-75 
0-25 


Potash. 

0-93 
2-06 
0-12 


Sulphuric acid. 
0-08 


Phosphoric acid. 

0-06 
0-17 

0-40 


0-02 




fa. 

- b. 

c. 


0-802 
0039 
0-715 


3-825 
0-490 
0-792 




0-042 
0-046 
0-007 


Beesdau, 




0-004 


Neuensund, 


t 


1-692 
0-614 
0-728 


3-531 
1-289 
1-243 


0-050 
0-038 
0-241 


0-051 
0-010 
0-121 


Turwe, 


\l 


2312 

2-67 

3-391 


1-112 

1-14 

0-201 


0-040 

0-03 

0-022 


0-057 

0-20 

0-014 


Frankenfelde, 


\l 


0-420 
1-081 
0-461 


1-155 


0-016 


0-004 
0-418 
0-071 


1-456 


0-015 



If we run over these figures and those of the entire series of 
analyses, we find that different determinations disagree to such 
an extent as to make it the sheerest folly to base any calculation 



8 S. W. Johnson on the Soil-analyses of the [240] 

of the value of the soil upon analysis. Some of the analyses 
agree sufficiently to show that accordant results are possible if 
uniform material be taken ; but the grand result of the investi- 
gation is that the difficulties of getting a uniform material are 
exceedingly great. Again, we must remember that in the case 
before us, the three examinations of each soil were made upon 
portions of one carefully mixed sample. What would have 
been the result had each chemist received a sample collected 
separately from all the others, and from different parts of the 
field ! 

Dr. Peter mentions these analyses of the Landes Collegium, 
and quotes a few of the results on page 187 of the 3d Kentucky 
Beport. He believes however that these discordant results do 
not invalidate soil analyses when made as they may be made 
with " means and appliances now at the service of the analytical 
chemist" and thinks "this statement however hazardous it may 
seem will be found to be sustained" in his Report. 

In the Report before us however we do not lind anything to 
sustain Dr. Peter's view. He gives, so far as we have discovered, 
no duplicate analyses, to show what accuracy his methods admit 
of on the same sample, much less does he prove by analyses of 
specimens separately gathered from the same field, that it is easy 
to procure an average material for analysis. Until this proof is 
produced the evidence is in favor of our view. 

Having shown how small an error in sampling may affect the 
chemist's estimate of a soil, it is not out of place to insist for a 
moment, that a similar error in the analysis itself, must have the 
same result. In running over 200 pages of Dr. Peters 4th Ken- 
tucky Report, we find five analyses of soil in which there is a 
gain of from five to eight tenths per cent; we find twenty -three in 
which there is a loss exceeding five tenths per cent. In thirteen 
of the latter the loss is eight or more tenths, in eight instances 
the loss is one per cent or more, and in one case is one and eight- 
tenths per cent. We should scorn to notice little matters like 
these, errors which are inseparable from the best manipulation 
and the best processes, were it not that in soil analysis it is pre- 
cisely the small quantities which alone have any importance. 

We find in Dr. Peter's work, as in the work of all who have 
preceded him in the analysis of soils from Davy and Sprengel 
down, evidence that the best endeavors in this line of research 
are entirely incommensurate with the desired results. 

It may be objected to this criticism of the analyses that the 
loss or gain must be distributed among the twelve ingredients 
determined. It is true that there is a probability that such dis- 
tribution would be just; but this is by no means certain^ and it 
is equally true that this being done there is still force in the 
criticism — for the four-tenths per cent of the soil which a cen- 



[241] Geological Surveys of Kentucky and Arkansas. 9 

tury of wheat crops would remove, likewise consists of twelve 
ingredients. 

The 2d result of these analyses, according to Drs. Owen and 
Peter, is what the former (4th Ky. Eep., p. 33) declares to_ be 
"a general law" " now established," viz., "that soil-analysis is 
capable of showing the exhaustion in land of the mineral food of 
plants by continual cropping.'''' 

To show the removal of soil-ingredients by cropping, the 
plan was followed of collecting soils from contiguous fields, one 
of which had been " cultivated" while the other was in its virgin 
state. On comparing the analyses it was found that in seventy- 
one* cases out of seventy-nine, a loss had occurred in the 
soil which had been in use without manure from ten to fifty 
years. In eight instances, however, the analysis failed to show 
such a result, owing to local causes, the soil of the old field 
being based on a sub-soil richer than was the virgin field, or the 
old field having received washings of more elevated lands, &c. 

The admitted richness of the old over the new soil in these 
eight exceptional cases, is expressed by hundredths of per cent, 
e.g., soil Nos. 982, virgin, and 983, cultivated, differ by 0'066 per 
cent of potash. Soils 1144 and 1146 by 0-032 per cent of phos- 
phoric acid. Soils 1204 and 1205 by 0*092 per cent phosphoric 
acid. Soils 1207 and 1208 by 033 per cent potash. Similar 
fractions likewise show the amount of deterioration in the other 
seventy -one cases. We adduce two instances pointed out by 
Dr. Peter in the 3d Kentucky Keport, p. 207, and one given on 
p. 176 of the 2d Arkansas Peport : 

Carb. of lime. Magnesia. Phosphoric acid. Potash. 

Virgin soil, No. 557, 0-345 0-335 O'lSlf 0-156 

Old soil, No. 558, 0-215 0-465 O-lOSf 0-101 

Difference, 0-130 0-130 gain. 0-078f 0-055 

Virgin soil, No. 738, 0-180 0-444 0-179 0256 

Old field, No. 739, 0-145 0-388 0-163 0-179 

Difference, 0-035 0-056 0016 0077 

Virgin soil. No. 288, 0-121 0-371 0-127 O'llS 

Old field, No. 289, 0-021 0-371 0-053 0-097 

Difference, 0-100 0000 0'074 0-019 

We were prepared to find these differences much larger. It 
is seen at a glance that they fall within the errors of Dr. Peter's 
own manipulation, and when we assert that of ten analyses of 
the most homogeneous material made by the same analyst under 
the most favorable circumstances, five would differ among each 
other by an amount equal to the quantities upon which this 
" natural law " is supported, we assert what every competent 

* Misprinted twenty-one, on p. 31, 4th Kentucky Report. 

f Misprinted on p. 207, 3d Ky. Rep, wliere the difference is made 0-045 instead 
of 078, as given above frona the tabulated analyses. 
Am. Jour. Sci.— Second Series, Vol. XXXII, No. 95.— Sept., 1861. 
31 



10 S. W. Johnson on the Soil-analyses of the [242] 

analyst knows to be true, and what moreover pronounces most 
emphatically upon the value of such investigations. 

It is therefore our conclusion, that while, as has long been 
known, the soil loses in mineral matter what the crop gains, it is 
doubtful if in any given case chemical analysis can indicate this 
difference with certainty, for the reasons that the accidents which 
affect analysis make the limits of inaccuracy, to cover more than 
the loss by years of cropping. When we take into account the 
changes that are constantly progressing in the soil when under 
cultivation — changes by which the disintegration is hastened, 
changes by which it is made in many instances more retentive 
of soluble matters — when we remember that most cultivated 
crops, although they carry oif in seed, stem and foliage a quan- 
tity of mineral matters, yet derive these in part from a depth 
below the range of analysis, and in their roots or stubble, leave 
upon the surface, salts brought up from a considerable depth — 
we perceive that the problem is so complicated with compensa- 
tions and variable quantities as to put it beyond the reach of 
quantitative chemical analysis. 

If, in any case, soil-analysis does show or appear to show the 
exhaustion of the soil, it is however, the appeal to experience 
which proves it, and as this is the first, most obvious, and an 
entirely sufficient proof, we do not see the value of the " law " 
that has 10 per cent (eight-seventy-ninths) of exceptions, the 
existence of which like that of the rule itself, is only to be 
established by comparison with the plain agricultural fact. 

In short, if we admit the result as Drs. Owen and Peter would 
have it — of what use or interest is it? 

The 3d point, is that analysis shows " the peculiarities of the 
soils derived from different geological formations." Says Dr. 
Owen, "these analyses most distinctly show that certain geolog- 
ical formations impart to the soil more of the important mine- 
ral fertilizers than others." The reader will be able "to see 
that it is those formations which are composed of easily disin- 
tegrating materials, which, all other things being equal, yield the 
soils richest in phosphoric acid, lime and potash; and at the 
same time contain the quantity of alumina and oxyd of iron 
necessary to render them sufficiently retentive and attractive of 
atmospheric water and ammonia; therefore these soils are the 
best adapted for those grains and crops which require the largest 
proportion of these ingredients." "He will moreover be able 
to trace the gradual diminution in the proportion of the more 
important mineral ingredients, down from these extraordinarily 
fertile soils derived from the highly fossiliferous, argillo-calca- 
reous beds of the lower Silurian, the Cretaceous and the Tertiary 
systems of the West; through the silico-calcareous soils of the 
upper Silurian, Devonian and Sub-Carboniferous limestone strata, 
in which fossils are either more sparingly distributed or, in some 



[243] Geological Surveys of Kentucky and Arkansas. 1 1 

cases almost wanting, and which are far less easy of decomposi- 
tion; thence through the argillo-silicious soils of the Coal meas- 
ures with only locally organic remains, and these chiefly of plants, 
down to the more purely silicious soils prevalent where the 
non-fossiliferous sandstones of the Coal measures and of the 
Millstone Grit, prevail to the exclusion of either shales or lime- 
stones and wfiich afford the most unproductive soils as yet an- 
alyzed." While it is to be expected that rocks of complex origin 
rich in organic remains — which are evidences that the rocks them- 
selves originally resulted from the deposition of the washings of 
fertile lands — should yield richer soils than sandstones or lime- 
stones, w^e do not see that analysis of the soil makes the fact 
more evident Knowledge of the composition of a rock enables 
us to judge in a general way of the value of the soil, so far as 
this depends upon chemical characters. We do not see what is 
gained by further analyses of the soil. It would appear that the 
cheap mental processes of deduction or inference may accomplish 
here in a moment all that an expensive analysis can show. 

We fail moreover to perceive that analysis shows " the pecu- 
liarities of the soils derived from the different geological forma- 
tions." In a cretaceous or limestone soil we of course expect to 
find much carbonate of lime, and in a sandstone or millstone grit 
soil much insoluble silica or silicates, but the quantities of phos- 
phoric acid, potash and sulphuric acid do not appear to bear any 
definite relation to their geological origin. It is impossible to 
represent the composition of the soil of any geological formation 
by a typical statement of percentages, or to point out its pecu- 
liarities further than by an undefinable more or less. Although 
Kentucky and Arkansas lie mostly or altogether beyond the 
influence of drift, yet the action of running water in its con- 
stant passage from hill-top to valley has to a great degree oblite- 
rated from the soils those peculiar differences to be found among 
the rocks from which they have been derived. 

A careful examination of the analyses recorded in the Arkan- 
sas survey shows that the average composition of the eight soils 
analyzed from the Lower Silurian and of the fourteen from the 
millstone grit, compare as follows, in regard to the more im- 
portant ingredients : 

Phosplioric Sulphuric 

Carb. lime. Ma;^nesia. acid. acid. Potash. 

Lower Silurian, average of 8 soils, 0-533 0-485 0184 0-052 0-355 

Millstone grit, " 14 " 0-215 0531 0180 0-057 0-148 

Here we see that the soils of the poorest formation are inferior 
to those of the richest only in carbonate of lime and potash. Of 
the soils of the millstone grit, nine are richer in carb. lime than 
the poorest of the Silurian, and five of the former contain more 
potash than the poorest of the latter. On the other hand but 
two of the Silurian soils have higher percentages of either carb. 



12 -S. W. Johnson on the Soil-analyses of the [244] 

lime or potash, than the richest soil of the millstone grit. If 
these figures demonstrate anything, it is the fact, that no geolog- 
ical formation has the absolute monopoly of either barren or 
fertile soils. If the analyses of Dr. Peter show the "peculiari- 
ties" of the soils of any geological age, then certainly these 
peculiarities are not remarkably peculiar! 

On page 50 of the 2cl Ark. Rep., Dr. Owen remarks as follows : 

" With the table of the composition of the ashes of plants to 
refer to, appended to this Report, and after becoming acquainted 
with the usual proportions of mineral constituents in an average 
soil, information which is easily acquired by looking over the 
table of soil analyses in this Report, it is easy for any individual 
to see, when he is provided with a reliable analysis of his soil, 
not only to what crop it is best adapted, but what kind of min- 
eral fertilizers, if any, it requires as a manure, and how it com- 
pares in fertility to the various grades of soils from other farms 
and other states. Is not this knowledge of some value to the 
farmer?" 

The above, we are of opinion, proceeded rather from the 
generous heart than from the critical brain of its lamented author. 
Had he attempted to do the things which he believed to be so 
easy, we are sure his statements would have lost somewhat of 
their directness and would have appeared in a form highly modi- 
fied from the above. " The usual proportion of ingredients in an 
average soil." What is an average soil? Our only way of 
deciding what is such a soil consists in noting the average yield 
of soils. But the yield depends not alone on the soil, but upon 
climate, weather, tillage and various incidents and accidents. It 
depends not on the composition of the soil — not on the "propor- 
tion of ingredients" alone, but likewise on the condition of 
those ingredients, their state of combination, their solubility. It 
depends also on the physical characters of the soil, which deter- 
mine the relations of the crop to the essential conditions of reg- 
ulated heat and moisture. The soil is not less important to the 
plant in its function of home than in its function of food, the lodg- 
ings are of equal influence with the board. It is a nice work to 
balance these varying circumstances, many of which have as yet 
in our science, no shadow of a numerical expression, and then to 
say how many thousandths of a per cent of potash, lime, phos- 
phoric acid, &c., belong to the "average soil." 

Dr. Peter has indeed attempted to show the degree of availa- 
bility of the elements of the soil by the following process. "A 
quantity, generally thirty grammes of the air-dried soil is 
placed in an eiglit-ounce strong vial, with a close fitting stopper, 
and the bottle is filled up with distilled water which has been 
charged with pure carbonic acid gas, under a pressure of about 
two atmospheres. The bottle is allowed to remain for about a 



[245] Geological Surveys of Kentucky and Arkansas. 13 

month at a temperature about that of summer heat." The 
matters thus dissolved were then analyzed as usual. These 
results have this value, they show that the water of the soil is 
capable of dissolving all the elements of the food of plants. 
They furnish moreover a rough comparative view of the availa- 
ble matters in different soils. Beyond this we cannot attach any 
value to them. 

We now come to Dr. Owen's 4th result of soil-analyses, 
embodied in the above quotation, and repeated on p. 30 of the 
4th Ky. Kep., viz: its power of indicating "the suitabilit}^ of 
the soil for any particular crop." Closely related to this is the 5th 
item, viz., that anaWsis can show " what addition any soil, either 
uncultivated or cultivated, requires to render it productive and 
remunerative for any given crop; and, of course, the deficiency 
in the soil of one or more of the eleven elements determined by 
chemical analysis." 

We cannot help feeling that the above assertions which are 
here made unqualifiedly, were intended to be understood with a 
large amount of reserve and subject to various conditions. Oth- 
erwise we must regard them quite unjustified, if not absurd. 
The chemical analysis of soil reveals nothing as to its tenacity or 
lightness, its porosity or retentiveness for water, j9t these phys- 
ical and mechanical conditions more than anything else determine 
the adaptation of a soil for any particular crop. The best grass 
lands are not the best wheat lands — and although it would 
scarcely be questioned that wheat requires a richer soil than 
grass in order to produce an average crop, and although as we 
know, it often happens that many successive hay crops may be 
removed from a meadow without sensible diminution of the 
yield, while uninterrupted cropping with wheat nearly always 
reduces the capacity of the soil in a very few years below a 
profitable point; yet each average hay crop removes from a field 
more of every ingredient of vegetation than the grain and straw 
together of an average harvest of wheat. 

Such at least is the testimony borne by the most recent and 
trustworthy data. Dr. Anderson of Glasgow basing his calcula- 
tions on the best analyses and on the extensive agricultural 
statistics gathered in late years by the Highland and Ag. Society 
of Scotland, makes the following estimate of the amount of the 
principal ingredients removed from an acre by average crops of 
seven staple British farm products. See table on next page. — 
Trans. Highland and Ag. Soc.., 1861, p. 568, 

On comparing the amount of matters removed from an acre 
by the wheat and hay crops, we find that the latter requires four 
times as much potash, lime and sulphuric acid ; twice as much 
silica and one-fifth more nitrogen. 

Again we know that oats are raised on soils which are consid- 
ered too poor for the profitable production of wheat, and the 



14 



iS. W. Johnson on the Soil-analyses of the 



[246] 



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[247] Geological Surveys of Kentucky and Arkansas. 15 

table shows us that an average crop of oats requires more of 
every mineral ingredient than is needful for a corresponding 
wheat crop. 

In fact, wheat is the crop, to grow which continuously requires, 
according to universal agricultural experience, land richer than 
that needed for any other of the seven crops whose chemical 
statistics are given in Dr. Anderson's Table, and notwithstanding, 
with exception of barley and the potato-tuber, it removes the 
least from the soil. 

The farmer knows that wheat delights in a deep, rather heavy 
soil, one which holds moisture well, and yet is not wet. Barley 
and oats flourish on soils that are too dry and light, and grass 
on those which are too wet for wheat. 

But how does the matter stand when these external conditions 
are taken into account? Does not analysis aid us then in a 
good degree? Let us take a case similar to what has repeatedly 
occurred in actual practice. We have a soil which as the result 
of long cultivation or from natural deficiencies, is incapable of 
yielding a remunerative crop of wheat. Its texture is good, it 
has produced wheat abundantly, and needs nothing but a little 
of the right kind of manure to restore its power of giving a 
crop. We put upon it Peruvian guano at the rate of 300 lbs. 
per acre, and the harvest is a good one. The entire addition to 
the soil is but gnlfsTToths = one hundredth per cent. The 
amounts of phosphoric acid, of alkaline earths and nitrogen 
added, are for each, but one six-hundredth per cent of the soil, 
taken to the depth of a foot. These quantities are rather minute 
for even the improved analysis of the present time to estimate 
successfully. 

Calculations like this show that the chemist cannot discrimi- 
nate by his analysis between; 1st, a soil which is unproductive 
from the temporary exhaustion of some of its available ingre- 
dients ; 2d, the same soil which is rendered fertile again for a 
year by the use of 300 lbs. of guano ; and 3d, the same, made 
over-rich so that nothing will grow on it, by an application of a 
ton of guano. 

On page 18 of the 2d Ky. Eep., Dr. Owen remarks as follows: 
"During last summer a soil was collected in Bullit county, from 
an old field which had been fifty or sixty years in cultivation, 
and which will now no longer produce clover. I venture to 
predict that when the analysis of this soil shall be completed it 
will be found to be deficient in some of these constituents,* and 
the analysis will probably show what other green crop might 
succeed better for the renovation of such land." 

On page 230 of the 3d Ky. Eep., Dr. Peter gives the analysis 
of this soil, and says, " The inability of this soil to produce clover 

* Tlie mineral ingredients of plants. 



16 S. W. Johnson on the Soil-analyses of the [248] 

is explained by its very small proportion of lime, and rather 
small amount of sulphuric and phosplioric acids. The addition 
of plaster of Paris or some of the calcareous marls would prob- 
ably restore it to the capability of supporting a clover crop." 

The percentages of the ingredients which Dr. Peter considers 
deficient, are as follows : 

Carbonate of lime, - - - 0-0'72 =lime 0-040 
Sulphuric acid, ... 0-055 

Phosphoric acid, . . . 0"070 

Small as are these quantities, the smallest of them, viz., that 
of lime, yet amounts to 1200 lbs. per acre, which is enough to 
supply 10 clover crops of 3 tons each, and as by the analysis it 
all exists in the form of carbonate, it must all be available. We 
know from the vegetation experiments of Boussingault, Ville, 
and Sachs, that plants are capable of absorbing from a limited 
amount of soil the whole of any soluble nutritive substance pres- 
ent, provided its quantity be no more than the plants require, 
and the other elements of fertility are at hand in excess. 

Twelve or thirteen years ago. Dr. Anderson in his capacity of 
Chemist to the Highland and Ag. Society of Scotland, had occa- 
sion to investigate two soils which had become " clover-sick," 
and he caused them, together with similar adjacent soils which 
still produced clover, to be most minutely analyzed. Without 
reproducing his figures, which may be found in the Trans, of the 
Highland and Ag. Soc. for 1849-51, p. 204, we will merely 
quote some of the remarks which accompany the analyses : " The 
results of these analyses are certainly of an unexpected charac- 
ter, and appear to me to indicate that, in this instance the failure 
of the clover cannot have been dependent upon the chemical 
constitution of the soil. In both cases the results of the analyses 
of each pair do not present a greater difference than would be 
obtained from the analyses of two portions of soil from different 
parts of any field." 

In the present year, Stoeckhardt (Chemischer AcJcersmann, 
No. 2, 1861, p. 85), "has published an account of several " clover- 
sick " soils from Schlanstaedt, which reveal to analysis a greater 
content of every nutritive mineral ingredient both soluble in water 
and in acids, than exists in another soil from Frankenstein which 
produces clover and wheat as well. What proves beyond a 
doubt that the inabihty of these soils to yield clover depends 
upon something besides their chemical constitution, is the fact 
that lucerne and esparsette still flourish upon them admirably, 
and further, clover itself, if sown with one of these last men- 
tioned crops, succeeds very well. 

A great truth in agriculture is this: Each kind of agricultural 
plant requires that its seeds be surrounded with certain conditions 
in order that they may germinate readily and healthfully, so 



[249] Geological Surveys of Kentucky and Arkansas, 17 

that when the mother cotyledons are exhausted, the young plants 
shall attack the stores of food in the soil with that vigor which 
is needful in order to appropriate them without hindrance. 

The fact that winter wheat is more delicate and fastidious in 
its infancy than most other crops, is perhaps the main reason 
why it does not succeed well on many good lands, and why it 
cannot be continuously produced from the same soil, year after 
year. It is a matter of experience that wheat requires a rather 
firm seed-bed : beans, oats and mangold-wurzel approach wheat 
in their requirements, while barley, peas and turnips are best 
suited in a light tilth. On the other hand, climate, weather and 
tillage so influence the character of the soil, that even on light 
lands, wheat may find all the conditions of its growth. The bed 
which is produced by inverting a clover sod, and allowing it to 
consolidate by time and rains, or by passing a heavy roller over 
it, is eminently adapted to wheat, even on a rather light soil. 

The fact that in the cases given above from Stoeckhardt, clover 
succeeded when sown with lucerne or esparsette, would indicate 
that, possibly, the condition of the seed-bed was the cause of 
failure. 

These and other facts which might be adduced to almost any 
extent, indicate sufl&ciently that chemical analysis alone, even if 
we admit its full nicety and accuracy, can at the best furnish us 
with a knowledge of but a few of many conditions which must 
cooperate in profitable agricultural production, and as a conse- 
quence, its part in guiding the farmer is but very subordinate. 
Taking into the account its evident uncertainty and clumsiness 
when applied to estimating the minute quantities which affect 
vegetable growth, the part it can play becomes still more subor- 
dinate — we hesitate not to say, insignificant. 

As we write, a fragment from a Scientific Journal brings to 
our notice a discovery which if real, strengthens our views in 
an unexpected manner. It is well known that iodine is so im- 
mensely diluted in sea-water — the soil of marine-plants — that 
none of our tests though they are among the most delicate, serve 
to detect it directly, and it is doubtful if it has been detected 
even in the highly concentrated mother liquors which remain 
after separating the crystallizable salts, yet the fuci find and 
accumulate it, and we must grant that it is present there for 
them, in sufficient quantity. 

Again, Prince Salm Horstmar several years since, in his ad- 
mirable researches on the influence of the individual mineral 
ingredients of plants on the development of oats and barley, 
found that he could not by any possibility exclude chlorine from 
his experimental plants. His soils and pots, the salts and water 
he fed his plants with were so purified that he could not detect 
this element in them, and yet he invariably discovered it in the 

Ail. Jour. Scr.— Second Seeies, Vol. XXXII, No. 95.— Sept., 1861. 
32 



18 S. W. Jufinson on the Soil-analyses of the [250] 

ashes of the plants. So too he found titanic acid in the produce 
grown on the most carefully purified soils. Now, it is mentioned 
in the " Chemical News " that he finds a few hundredths of lithium 
are indispensable to the ripening of barley. This element Bunsen 
has but recently shown to be everywhere distributed, yet it has 
been hitherto entirely unnoticed in all soil- and plant-analyses 
because of its occurrence in almost infinitesimal quantity. 

It must be well borne in mind that Agriculture herself — so- 
called Practice — is able of her own resources to judge somewhat 
of the value of soils, is able to know if a soil be fertile or poor, 
is able to pronounce upon its adaptation to crops, and can to a 
certain extent decide what is a good manure for this or that field. 

We are free to assert that the knowledge which is now to be 
gathered from experience, is able in ninety-nine cases out of one 
hundred, to give a more truthful verdict as to the capacity of a 
soil, that any amount of analysis, chemical, mechanical or other- 
wise, can do. We would give more for the opinion of an old 
intelligent farmer than for that of the most skilled chemist in 
most questions connected with farming. Doubtless the farmer 
would make some blunders from which chemistry might save 
him, but the chemist would be likely to do more violence to 
agriculture, than the farmer would to chemistry. 

By these statements which may, but should not surprise some 
of our scientific friends, we merely intend to express an opinion 
as to the present relative position towards agriculture of those 
who regard the art from a chemical, and those who see it from an 
experimental point of view. 

If any one has fuller and more inspiring notions of the import- 
ance of science in its applications to agriculture than we have, 
we desire to sit at his feet and share the higher afflatus. But our 
inspiration, if it be of the sort that works enduring benefit, must 
be based on clear ideas of the directions in which advance is 
possible and on a full perception of the difficulties that lie before 
us, and the means of overcoming them. 

We have great faith that chemistry and that chemical analysis 
have done and are to do a work for agriculture, that shall lay that 
venerable art under everlasting obligations to the youthful sci- 
ence. But not by soil-analyses alone or mainly is this to be 
achieved. We do not assert that soil-analysis is worthless — we 
believe that the probabilities of its uselessness in direct applica- 
tion to practice are so great that we would rarely base any ope- 
rations on it alone, and yet it may in many cases, promote science 
and give us data for conclusions that are of practical use. But 
for these purposes it must form part of a system of observations 
and trials, must be a step in some research, must stand not as the 
index to a barren fact, but as the revelator of fruitful ideas. 

We hold that soil-analysis long ago pla3''ed out the part which 
Dr. Peter would have it perform. In the hands of Sprengel it 



[251] Geological Surveys of Kentucky and Arkansas. 19 

was fertile with new truth, but it must henceforth be a tool for 
occasional use, and not an engine of discovery. With our ad- 
vance in knowledge there must be an advance in methods of 
finding out the unknown. Soil-analysis was indeed a means of 
insight into the secrets of vegetable growth, but it carried with 
it the measure of its limit. What we call telescopes do not ena- 
ble us to see the end ! 

To study the soil in the hope of benefitting agriculture, we 
must regard all its relations to the plant. We must examine it 
not merely from those points of view which theoretical chemistry 
suggests, but especially from those which a knowledge of prac- 
tical agriculture furnishes. This is becoming more and more 
the habit of agricultural chemists and the results are of the 
happiest kind. 

Let us remember what the illustrious Nestor of Agricultural 
Science, Boussingault, has said as the summing up of his pro- 
tracted experience and study. 

" At an epoch not far distant it was believed that a strict 
connexion existed between the composition and the quality of 
arable soil. Numerous analyses shortly modified this opinion as 
too positive. The sagacious Schiibler even sought to prove in a 
research that has become classic, that the fertility of a soil de- 
pends more upon its physical properties, its state of aggregation, 
power of absorption, &c., than upon its chemical constitution." 

" The physical properties, in my opinion, do not enable us, 
more than the chemical composition, to pronounce upon the de- 
gree of fertility of the soil. To decide this point with some meas- 
ure of certainty, it is indispensable to have recourse to direct ob- 
servation ; it is necessary to cultivate a plant in the soil, and 
ascertain with what vigor it developes there: the analysis of the 
plant afterward intervenes usefully, to indicate the kind and quan- 
tity of the elements that have been assimilated." — ("i^e la Terre 
Vegetale consideree dans ses EffHs sur la Vegetation^'''' page 283 of 
'•^Agronomie, Chiniie agricole et Pkysiologie.^ Tome 2^remier, I860.") 

There has been much progress made in our knowledge of the 
soil during the last ten years. This advance has not consisted 
in reveaHng to us the presence of new elements (lithia perhaps 
excepted), nor in fixing with any more certainty the quantitative 
limits which separate barrenness from fertility, it has not shown 
what is the composition of a Silurian or a Sub-Carboniferous, a 
Drift or a Tertiary soil, it has not defined the soil adapted to 
wheat or that productive of clover, it has not indicated the ma- 
nures which this or that soil needs; but content with the fact 
that all soils which naturally support vegetation contain the 
elements of vegetation, it has sought to ascertain in what forms 
these elements are assimilable, how they may be made available, 
what changes or reactions in the soil affect its productiveness; 
how fertilizers act indirectly (their influence often having no 



20 5, W. Johnson on Soil-analyses, etc. [252] 

relation to any supposable direct action), how the soil affects the 
life of the plant otherwise than by feeding it, &c. &c. 

We are approaching in fact by slow degrees to an understand- 
ing of the physiological significance of the soil, a grand result 
to which chemistry and physics cooperate. 

We trust that in the future, the American people will not less 
but more appreciate the value of science in its practical and es- 
pecially its agricultural bearings; that here, as in Germany, 
France and England, the labors of those who seek to unite Prac- 
tice with Science may be fostered and sustained. But to this 
end scientific men must be cautious that in endeavoring to help, 
however honestly and laboriously they may work, they do not 
hinder. 

Sheffield Scientific School, August 20th, 1861, 



LIBRARY OF CONGRESS 




